The present invention relates to an improved method and apparatus for mass-producing an electroplated wire or the like of high quality at high efficiency.
There is a great industrial demand for electroplating the conductive metal wires of various kinds or the like. The electroplating of a certain thickness requires a definite time for the electroplating which is determined by the kind of the electroplating bath and other conditions thereof. Therefore, the requirement of a thick plating and/or a high line-speed for the purpose of the mass-production makes it necessary to maintain the wire or the like to be treated in the electroplating bath over a long distance.
On that occasion, since the amount of electricity supplied to the wire to be treated is defined by the diameter of the wire and the conductivity, it is necessary to feed electricity to the wire from a plurality of power sources by division.
Accordingly, there has been generally used the electroplating apparatus which runs the wire horizontally and has scores of the plating cells arranged in series, and a power supply section between the cells. However, such electroplating apparatus requires a large space and is disadvantageous economically.
Then, there might be the arrangement of running the plural wires in parallel to each other through the same cell in order to reduce the number of cells. In this case, many expensive devices for both pay-out and take-up are necessary if the number of cells is reduced, and therefore the problem is not satisfactorily solved.
Under these circumstances, the following apparatus have been proposed by the Japanese examined publication Sho No. 46-22082, U.S. Pat. No. 3,676,322 to Kamata and B. Pat. No. 1,302,793 in which the wire to be treated is wound on a pair of drums having a vertical and rotatable shaft respectively in multiple stages and made to pass many times through the electrolytic treatment cell positioned between the drums while power is supplied to the wire through the drums.
Further, in addition to the above apparatus, a method in which more than three drums are arranged circularly and electroplating is carried out by winding the wire on these drums.
The method using the vertical and rotatable drums in Japanese examined publication Sho No. 48-34286 proposes industrially more advantageous means than those using the horizontal and rotatable drums because in the former method the anodes are arranged on the right and left sides in the electrolytic cell to put the wire to be treated therebetween and further are supplemented and exchanged from the upper part of the cell.
In the method using vertical and rotatable drums, in order to keep the wires in multiple stages guided in and out of the electrolytic cell with a height between the wires sufficient to immerse those wires in the electrolyte of the cell, the wires are pressed by the elastic packing such as rubber and plastics on both sides of the wires at the end of the cell to close up. The method of pressing the packing to the wires directly causes the troubles on the quality, such as scratches and cracks formed on the surface of the wire, and foreign matters entrained on the surface of the wire and mixing into the plating during the process of the plating.
On the other hand, the number of the turns per pair of drums is limited by the operational problem that wires wound are entangled by change of wire tension.
Then, the method of passing the wires in multiple stages through a narrow slit instead of the packing has been tried but rather resulted in increased entanglement of the wires in most cases.
As mentioned above, the amount of the wire to be wound on a pair of the vertical and rotatable drums is practically limited and the method is unfavorable to the mass-production.
Then, the arrangement of employing more than three drums may be thought of. In this case, the number of electroplating tanks is increased in proportion to the number of the drums and, on the other hand, the winding angle of the wire to the drums is decreased such that the electric supply to the wire becomes improper and the production quantity is naturally limited.